In 1950, a series of new United States highways were voted upon by the organization that controlled such things at the time, the American Association of State Highway Officials, or AASHO. That organization is not one of the Federal government, but one that is actually the states (and Washington DC and Puerto Rico) getting together to set standards and keep track of interstate and US highway numbers. (There is a lot more to it, but I want to get to the point!)
Whenever a highway is added or removed to the interstate or US highway system, it has to have approval of AASHTO (the successor to AASHO, with the words “and Transportation” added in 1973). When US 33 was removed from Indiana and Michigan, while the two states agreed, it had to be approved by AASHTO. The same for US 460 when it was truncated at Frankfort, Kentucky, leaving the rest of Kentucky, Indiana, Illinois, and Missouri without that highway that was basically replaced by Interstate 64.
So, in 1950, some new US highway was added to the system. These highways were “daughters” to other routes. For instance, US 136 would be the first branch off of US 36, with 136 starting in Indianapolis, and US 36 originally starting there. But today, I want to look at another road that came through Indianapolis for a time…US 421.
When the Indiana State Highway Commission was created (the second time) in 1919, the first state road added to the highway system after the first five Main Market roads was the Michigan Road Auto Trail, slightly different from the Historic Michigan Road, from Madison, through Versailles, Greensburg, and Shelbyville to Indianapolis. The original State Road 6 continued north from Indianapolis via the Lafayette Road, but that is not part of this profile.
On the northern end, original SR 15 connected Michigan City to Logansport via Laporte, Knox and Winamac. In 1923, with the first Renumbering, the Historic Michigan Road from Logansport to Indianapolis was added as an extension of OSR 15. This created a route that connected the same destinations without going the same direction. The Historic Michigan Road connected Logansport to Michigan City via Rochester, Plymouth and South Bend. The new original State Road 15 used a direct course between the two.
Meanwhile, the original State Road 6 from 1920 would come into this story by connecting Frankfort to Monticello through Rossville and Delphi. With the renumbering of 1923, that route would be given the number 44, the original number of what would become the rerouted Lincoln Highway (and US 30).
With the Great Renumbering of 1 October 1926, entire route of the old Michigan Road Auto Trail from Logansport to Madison was given the number 29, as was the original State Road 15 from Logansport to Michigan City. The old state road 6/44 that connected Frankfort and Monticello was given the number 39.
To other roads that would become part of this story were shown as authorized additions to the state highway system. First was the road that connected the Michigan Road near Boylestown to Frankfort was to be added as State Road 28, which at the time connected US 31 west of Tipton to SR 9 north of Alexandria. The other was to be added as SR 43 north from Reynolds along the new US 24 due north to Michigan City.
Meanwhile, the original Michigan Road route from Logansport to Rochester was an authorized addition to the state highway system as SR 25. The rest of the route, from Rochester to Michigan City had been part of the system since 1923, most having been part of the system since 1917. Original State Road 1 (later US 31) from Rochester to South Bend was an original Main Market Road, as was Original State Road 2 from South Bend to Rolling Prairie. The section from Rolling Prairie to Michigan City would be added as OSR 25, and the section from Rolling Prairie to South Bend would be given the number 25 as well, since the number 2 was moved to what would later become US 30.
So now that we have the history of the route nailed down, let’s get to the topic of this post.
On 25 January 1951, it was announced that road markers had arrived from the renumbering of several state highways to a new number: US 421. At the time, US 421, a daughter of US 21 that connected Cleveland, Ohio, to Hunting Island, South Carolina, ended at Bristol, Tennessee. The road itself had been truncated to Bristol, as it had previously connected to the Cumberland Gap in Virginia. And once again, it would cross Virginia, on its way to Lexington and Milton, Kentucky, to cross the Ohio River into Madison, Indiana.
Once in Indiana, it would follow the Michigan Road Auto Trail route (again, not entirely the Historic Michigan Road) to just south of Boylestown. This would take the new US highway through Versailles, Greensburg, Shelbyville and Indianapolis. This was the route of SR 29.
At the point south of Boylestown, US 421 turned west for seven miles to enter Frankfort along SR 28. At Frankfort, the new highway would turn north along SR 39 to US 24. West along US 24 to SR 43, then north along SR 43 to Michigan Road.
On 13 March 1951, the new US 421 was officially marked along the route mentioned above. All official press releases for the marking of the route made sure to point out that the old route numbers would be used along the new route until 1 July 1951 to avoid confusion. Thus from Boylestown to Madison, the road would have two numbers: US 421 and SR 29. At least for a while. It would seem that the only two road numbers that would removed would be SR 29, located as above, and SR 43 from US 24 to Michigan City. SR 28 is still, to this day, labelled as such along the US 421 route. And SR 39 is multiplexed with US 421 from Frankfort to Monticello.
From Indianapolis, this new US highway would create the third route with a Michigan City end. And all three followed the Historic Michigan Road out of the city. At Boylestown, US 421 separated from the historic road to follow the route above. At Logansport, SR 29 left the historic route by travelling northwest across the old swamp land that caused the road to turn toward Rochester in the first place. Meanwhile, the original road continued along its old path, connecting to Rochester as SR 25, then to South Bend as US 31, and on to Michigan City as US 20.
The SR 29 route would be changed, as well, to a US Highway from Logansport to Michigan City…when it would become part of the US 35 route. By 1935, the number US 35 was multiplexed with SR 29 from Burlington (west of Kokomo) to Michigan City. In 1942, the section from Burlington to Logansport would go back to being just SR 29, as US 35 was rerouted along the new SR 17 connecting Kokomo to Logansport directly. The SR 29 designation would be truncated to Logansport, thus removed from the US 35 route, sometime in either late 1957 to 1958. The Indiana Official State Highway Map of 1959 shows no multiplex of US 35 and SR 29.
Over the 170 years of its existence, the Michigan Road has been an important route. The city of Michigan City was created to be a point of destination for the road. As technology improved, this important route would be replaced and shortened. Today, the US Routes of 20, 35 and 421 are the ends of the different routes connecting Indianapolis (more or less) directly to Lake Michigan at Michigan City.